The presented invention relates to medications containing as effective substrate phosphatidylcholine in an amount sufficient to treat diseases in which the mucosa-protective effect of phosphatidylcholine in colon and terminal ileum (including pouch mucosa) is of advantage. The medications are suitable for treatment of ulcerative colitis, pouchitis, other inflammatory diseases of colonic mucosa (Crohn""s disease; diversion colitis; infectious enteritis/colitis; mucosal inflammation by irradiation, antibiotics, chemotherapeutic or pharmaceutical agents, chemicals) as well as for prophylaxis of colon cancer.
Chronic inflammatory bowel diseases, ulcerative colitis and Crohn""s disease, affect in high degree young and medium-age adults with increasing frequency (prevalence of both diseases 1-2%). A chronic course with acute inflammatory episodes and numerous complications (development of fistulae and abscesses, stenoses, acute inflammations, bleedings, functional impairment of colonic mucosa, extraintestinal manifestations) characterize the natural course of these diseases. In particular, it is emphasized that ulcerative colitis after long-term course is associated with an increased risk to develop colonic cancer. Despite intensive research, the pathogenesis of these diseases could not be determined until today. Therefore only a symptomatic therapy is available which is not directed towards the cause of the disorder and often does not provide the desired success.
Between ulcerative colitis and Crohn""s disease exist major differences, such that one can assume 2 different pathogenetic mechanisms. Crohn""s disease can principally affect the entire gastrointestinal tract (main localization at the end of small intestine in terminal ileum). Inflammatory changes are localized circumscriptively in an otherwise healthy mucosa and can change with time. Main complications are inflammatory stenoses of intestinal segments as well as development of fistulae or abscesses. Manifestations outside the gastrointestinal tract are possible. Ulcerative colitis, in contrast, reveals a continuous inflammation with superficial ulceration starting at the end of the colon (proctum, rectum). According to severity of inflammation the colitis can spread upwards and finally the total colon can be affected. In high percentage also the end of the small intestine can be affected (xe2x80x9cbackwash ileitisxe2x80x9d). Main complications are functional impairments of colonic mucosa associated with frequent diarrhea, bleedings of mucosal ulcerations and rarely dramatic inflammation of the entire mucosal wall (toxic megacolon). Frightening is the frequent development of colonic cancer after long-term course of the disease. Between both chronic inflammatory bowel diseases, an overlap of symptoms can be observed such that discrimination is often very difficult. Beside the often-insufficient symptomatic therapy in ulcerative colitis it is frequently necessary to remove the entire colon because of a complicated, severe clinical manifestation or the threatening danger of carcinoma development. This procedure includes construction of a reservoir (pouch) out of the last ileal loop, its positioning into the anal channel, fixation in this position and connection to the natural anus (after removal the rectal mucosa). This allows creation of a new reservoir for intestinal contents with the advantage to maintain the natural outlet (continence maintaining ileo-anal pouch construction). In about 30% of patients with ulcerative colitis the pouch can get inflamed (pouchitis) and can lead to significant complaints. When such a pouch construction is performed in other underlying diseases (e.g. familial adenomatous polyposis) only in exceptional cases inflammation develops.
WO 95/18622 describes the use of derivatives of 2-hydroxy-5-phenylazobencoic acid as chemoprotective substance for treatment of diseases of the colon.
It was the task of the present invention to provide additional medications for treatment of bowel diseases. Of surprise was the observation that phosphatidylcholine functions as mucosa protective substance. Like a protective layer phosphatidylcholine covers the mucosal cells and is therefore suitable as therapeutic substance for treatment of ulcerative colitis, pouchitis, other inflammatory bowel diseases (Crohn""s disease, diversion colitis, infectious enteritis/colitis, inflammation due to irradiation, antibiotics, chemotherapeutic agents, pharmaca or chemicals) or for prophylaxis of colonic cancer.
Phosphatidylcholine (PC) (synonymously also the term lecithin is used) is a compound phosphorous containing lipid (phospholipid) with following schematic structural formula: 
where
R1=a saturated or unsaturated fatty acid with 14-22 carbon atoms, and
R2=a saturated or unsaturated fatty acid with 14-22 carbon atoms.
For treatment of ulcerative colitis, pouchitis and the other above mentioned bowel inflammations oral preparations of phosphatidylcholine are suitable with specific or delayed substrate release in lower ileum and colon and/or rectal forms of application, e.g. as clysmas, suppositories or foam. For prophylaxis of colonic cancer, particularly in association with ulcerative colitis, oral application is preferred. Oral applications can be provided in form of suitable preparations, e.g. as tablets or capsules which prevent absorption from the first two thirds of the small intestine and lead to specific release in the lower part of the ileum.
Medications containing phosphatidylcholine can be provided locally as rectal applications (e.g. suppositories, foam or clysmas) or orally. The application of phosphatidylcholine occurs in lower ileum sections and colon, mainly to protect the colon mucosa against bacterial infection. For oral application such medications are particularly suitable which release the effective substrate in a delayed fashion (retarded preparations). This retardation of effective substrate release is most usefully achieved by covershields and/or carrier matrices whichare gastric acid resistant and release the effective substrate in pH-dependent fashion into the lower ileum or colon. From a technical point of view, film covershields are suitable which contain as an example Eudragit(copyright)-acrylpolymers for directed release of the effective substrate in lower intestine or colon (e.g. the products with the brand name Eudragit(copyright)L and Eudragit(copyright)S from Fa. Rxc3x6hm, Darmstadt, Germany).
For preparation of orally applied phosphatidylcholine it is advantageous to use delayed released formulas to prevent absorption in proximal small intestine. Phosphatidylcholine could be packed in high volume (e.g. 0.88 ml content) capsules (e.g. made of gelatine). Those can be covered with arylpolymers, e.g. the above mentioned Eugradit(copyright)-preparations. A combination of Eudragit(copyright)S and L-preparations (e.g. Eudragit(copyright)L/S 100) guaranties a delayed release at pH  greater than 6.4, as it is present in terminal ileum. The use of Eudragit(copyright) preparations and their mixture (L-, S- and R-preparations) is established since a long period of time. In addition it is possible that also other covershield materials or application forms (also new developments) can be used for specific release of phosphatidylcholine in terminal ileum if they are proven to provide the best solution to the problem.
For preparation of clysmas phosphatidylcholine (lecithin) preparations can be solved in lipophilic solution media (e.g. soya oil). The applied dosage may for example range from 5-20 g in 100 ml soya oil. 100 ml of this solution can be applied rectally as clysma. In addition, suppositories or foam preparations can be used as application forms.
Subject of the invention are medications containing phosphatidylcholine in therapeutic effective amounts which is sufficient to achieve a mucosa protective effect in colon. The content of the effective substrate in the final preparation amounts 1-500 mg, preferentially 100-300 mg. For oral application suitable formulas are tablets, granulates, capsules, pellets or pellet tablets. The forms of medication can further contain usual pharmaceutical additions, such as supportives or carrier substances. For the rectal application primarily suitable preparations are clysmas, foam preparations, ointments, gels, lotions and suppositories. These contain the effective substrate in amounts of 10 mg-10 g, preferentially up to 5 g. According to the severity of the disease the formulas are applied once or several times daily.
Issue of the present invention is in addition a diagnostic procedure to detect diseases which are associated with reduced secretion of phosphatidylcholine in the intestinal lumen, e.g. ulcerative colitis, pouchitis (in ulcerative colitis patients) or diversion colitis. In this context, the present invention relates to a procedure to determine the phosphatidylcholine concentration in mucus of colonic mucosa, where the probe to be analyzed can be obtained by means of a dab sample of rectal mucus. Thereafter the probe will be analyzed by a suitablelipidchemical determination, e.g. by mass spectroscopy for analysis of the lipidcomposition.
It was of surprise to find that as indicator for the mucosa protective effect of phosphatidylcholine in intestine the determination of MDR3 analogous proteins is of diagnostic significance (MDR=multi drug resistance). The lack of MDR3 analogous proteins in terminal ileum can represent in this context an indicator for insufficient phosphatidylcholine secretion into the intestinal lumen with consequent change of the colonic mucus composition and increased susceptibility to local bacteria. Insufficient production of MDR3 analogous proteins thus may explain the reduced amount of phosphatidylcholine in intestinal lumen. In the sense of the presented invention, it could be shown that in mucosal epithelium of the terminal ileum or of the pouch of patients with ulcerative colitis, no MDR3-analogoos protein is present. Therefore, phosphatidylcholine secretion is significantly impaired as demonstrated by incubation experiments with biopsy probes. Accordingly, another issue of the present invention is the determination of MDR3-analogous proteins in terminal ileum and pouch for diagnosis of ulcerative colitis. This includes also all diseases associated with reduced presence of MDR3-analogous proteins.
The determination of the concentration or amount of MDR3-analogous proteins may also allow conclusions for the required optimal doses of phosphatidylcholine during the course of treatment with the invention related medications. Thus this diagnostic procedure enables an individual adaption of the required dosis of phosphatidylcholine for treatment of the patients.
Moreover, the determination of phosphatidylcholine in intestinal lumen may also allow control of therapy under the aspect of compliance of the patients.
The determination of MDR3-analogous proteins is indirectly performed by use of RT-PCR amplification of the coding RNA (genetic information).
The MDR3 protein or the MDR3-related proteins represent phospholipid transporters in plasma membranes. The human MDR (P-glycoprotein) gene family consists of two members (MDR1 and MDR3). Phylogenetically they belong to the very old super family of ABC transporters (ATP-binding-cassette). These proteins transport most diverse substrates (hydrophobic molecules, oxyanions, Clxe2x88x92 etc.) from inside of cells across the plasma membrane to the outside by expenditure of energy (ATP). In the genome both homologous MDR genes are positioned close to each other (MDR3 about 30 kb downstream of MDR1) and span together a distance of about 230 kb. Both genes consist of 28 exons,in MDR3 27 of these contain the coding region. Four splice variants of the MDR3 gene are known, each of which leaving the reading frame intact. In the variant Cxe2x88x92141 the complete exon 23 is missing, thus leading to a coding region which is shortened by 141 nucleotides. Exon 23 contains the transmembrane domain 11. A deletion could lead to a protein with completely different membrane topology. In MDR3 expressing tissues, the normal transcript and its variants are mostly present in equal abundancy.
The product of the MDR1 gene is responsible for resistance development towards different cytostatic drugs and thus gave the family the name: multidrug resistance (MDR). MDR3 is a membrane associated, 170 kD, energy dependent efflux pump for different lipophilic substances. Comparable to the other members of the ATP transporters, MDR1 consists of two homologous halves, each with 6 transmembrane domains and one nucleotide binding site.
MDR3 is identically structured, but reveals another tissue specific distribution pattern as well as another function, since it does not lead to xe2x80x9cmultidrug resistancexe2x80x9d. In mice in which the corresponding mouse specific gene (mdr2) is turned off (knock-out mouse model), a complete inability of the liver to secrete phosphatidylcholine into bile was detected. It was concluded that also MDR3 P-glycoprotein is responsible for transport of phosphatidylcholine out of liver cells into bile. About the presence of MDR3 in the remaining gastrointestinal tract nothing has been reported in the literature yet.